Does the R SIM cards really work or is it a hoax?

I decided to not donate anymore money to us cellular and the consequence is having a phone under a 2 yr contract that won't work until u pay the money owed. I have put well over 2,000 for three I phones to be on a plan for just under a year now. I think I have paid for our phones more than 2 times thier worth in phone bills. I don't think it's fair when they have just ripped me off left and right. Help please!!